Electrical relay



Dec. 14, 1948. DQDD 2,456,112

ELECTRICAL RELAY Filed Nov. 2'7, 1945 [maid/ion 6a Id lnralafiozz a j: FL .2. A (35$: 1 y

H15 ATTORNEY Patented Dec. 14, 1948 2,456,112 ELECTRICAL RELAY Arthur E. Dodd, Edgewood, Pa., assignor to The Union Switch & Signal Company, Swissvale, Pa., a corporation of Pennsylvania Application November 27, 1945, Serial No. 631,160

4 Claims.

My invention relates to electrical relays, and particularly to contact'mechanisms for electrical relays.

More particularly, my present invention relates to contact mechanisms for relays of the variety usually referred to as L or telephone" type relays, and has for an object'the provision of a contact mechanism whereby an electrical circuit controlled thereby will be'come closed during operat'ion'of the contact'niechanismin one direction only."

Another object of my invention is to provide a contact mechanism including a normally closed and a'normaily open contact so arranged that the normally closed contact will open after the normally open contact closes during operation of the contact mechanism in one direction, and will subsequently remain open until .after the normal-. ly open contact opens during operation of the contact mechanism in the opposite direction.

'A further object of my inventionis to provide a contact mechanism of the type described in which each contact includes a relatively fixed and a relatively movable contact finger and in which the relatively movable contactfingers are connected by a toggle link which causes the normally closed contact to function with a snap action due to the inherent resiliency of the movable contact fingers.

Other objects and characteristic features of my invention will become apparent as the description proceeds.

I I shall describe one form of contact mechanism embodying my invention, and shall then point out the novel features thereof in claims.

In the accompanying drawings, Fig. 1 is a view showing in side elevation a relay provided with one formof contact mechanism embodying my invention. Fig. 2 is a top plan view of the relay and contact mechanism shown in Fig.1. Fig. 3.

is a view in side elevation of the relay shown in the preceding views with the parts in the opposite extreme positions from that in which they are shown in the preceding views.

Similar reference characters refer to similar parts in all three views.

Referring to the drawings, the reference character A designates an L or telephone" type relay which in the form here shown comprises an L- 'shaped backstrap I of magnetizable material having a short le'g la and a long leg lb. A magnetizable core 3 is fastened to the short leg la of the backstrap I by a machine screw 4; and this core extends parallel to the long leg lb and carries an operating winding 5. Pivotally, mountedv at the free or forward end of the long leg lb of the backstrap l is an L-shaped armature 6, the legs 6a and 6b of which are substantially equal in length. The leg Ga of the armature 6 coacts with the free end of the core 3, while the leg 6b in the deenergized position of the armature extends substantially parallel to thelong leg lb of the backstrap I. As here shown, the leg 6b of the armature 6 is formed with two parallel side por tions 60. The armature 6 is pivotally attached to the backstrap l by means of a plate 8 which is fixed to the backstrap lb by screws 8a, and which projects beyond the free end of the leg lb. The projecting portion of the plate 8 is provided with two oppositely disposed recesses 9 which receive the two parallel portions of the armature 6 whereby the armature is hinged to the backstrap l without trunnions.

The armature 6 actuates contact mechanism embodying my present invention, which contact mechanism in the form here shown comprises four flexible contact fingers l0, ll, l2 and I3 clamped at one end in superposed parallel spaced relation between insulating spacing blocks H s ecured by means of screws ii to the long leg lb of the backstrap l at the end opposite to the armature 6. The contact finger lll cooperates with a plate 8b of insulating material attached to the leg 6b of the armature 6, and this finger is so adjusted that it presses against the plate 8b with sufficient force to swing the leg 6a of the armature 6 away from the free end of the cor 3 when winding 5 is deenergized. It will be apparent, therefore, that when the winding 5 becomes energized, the resultant upward movement of the.

insulating plate 8b will cause corresponding upward movement of the contact finger Ill. The contact finger 10 carries a low resistance contact button Illa which cooperates with a low resistance contact button lla provided on the free end of the contact finger l I. This latter finger is so adjusted that when the parts occupy the positions which they occupy when the winding 5 is deenergized, as shown in Fig. 1, the two contact buttons lOa and lla will be separated by an air gap so that the contact formed thereby will be open, but that when the armature 6 moves to its attracted position in response to energization of the winding 5 as shown in Fig. 3, the resultant upward movement of the contact finger l0 will cause the contact button llla to move into engagement with the contact button lla at .an intermediate point in the stroke of the armature to thereby close the contact formed by the contact buttons l0a and I la. A relatively stifi metal stop 3 I 8 is clamped between the insulating blocks l4 directly below the contact finger l I, and this stop cooperates with the finger II to accurately determine the position in the stroke of the armature at which the contact button Illa will move into .or out of engagement with the contact button lla.

Formed on the free end of the finger I is a U-shaped return bend I 0b the upper leg Inc of which extends into a V-shaped notch [5a formed in one end of a toggle link IS. The other end of the toggle link I5 is provided with a similar V-shaped notch lib which receives the free end of the finger l2. The U-shaped return bend lob is of such length and the parts are so proportioned that when the armature 6 is swung to its released position due to the bias of the finger ID, the end of the toggle link which is connected to the finger ID will be swung below the plane to which the finger I2 is biased due to its inherent resiliency and the free end of the finger l2 will be moved some distance above this plane. The parts are further so proportioned that when the armature moves toward its attracted position, the resultant upward movement of the finger l0 will cause the end of the toggle link which is connected to the finger II! to move above the plane of the outer end of the finger l2 at some point in the stroke of the armature after the contact button Illa has moved into engagement with the contact button Ha, whereupon the finger I! will snap downwardly due to the toggle action of the toggle link to a position in which the free end of the finger I2 is disposed below the plane to which it is biased by its inherent resiliency.

The contact finger I3 is provided at its outer end with a contact button l 3a which cooperates with a contact button lZa provided on the finger l2, and is so adjusted that when the parts occupy the position which they occupy when the winding 6 is deenergized, the two contact buttons I2a and He will engage each other to form a normally closed contact, but that when the parts occupy the positions which they occupy when the winding 5 is energized, the button l2a will then be moved out of engagement with the button l3a so that the contact formed by the buttons 12a and l3a will then be open. A fixed stop I! is clamped between two of the insulating blocks H directly below the finger l3 to accurately determine the position in the downward stroke of the finger l2 at which the contact formed by the contact buttons l2a and l8a will open, and two other stops l8 and I9 are clamped between two of the blocks M on opposite sides of the finger H to limit the upper and lower extreme positions of the finger l2.

With the contact mechanism constructed in the manner just described it will be apparent that the two contact fingers l0 and II comprise a slow moving normally open type of contact, whereas the two fingers l2 and I3 comprise a quick acting normally closed type of contact. It will also be apparent that when the relay becomes energized, the contact comprising the fingers l0 and II will become closed for a brief interval of time before the contact formed by the fingers l2 and I3 becomes opened. It will further be apparent that when the relay becomes deenergized after having been energized, the parts will return to the positions in which they are shown in Fig. 1 due to the inherent resiliency of the movable contact fingers and the above described proportioning of the parts, and that during this movement the contact formed by the contact buttons I (la its terminals is connected in series with the two and Ila. will open before the contact formed by the contact buttons 12a and Ha closes. It follows, therefore, that I have provided a contact mechanism by virtue of which an electrical circuit can be made to become closed during operation of the contact mechanism in one direction only.

One application of such a contact mechanism for railway signaling purposes is illustrated in Fig. 1. As here shown, a bell D with a'high capacity electrolytic condenser C shunted across contacts of the contact mechanism in an electrical circuit which is supplied with current from the terminals B and X of a suitable source not shown in the drawing. With the bell connected in this circuit in the manner shown when the relay A picks up, the condenser C will become charged during the interval in which the two contacts are closed while the armature is picking up and will discharge through the bell as soon as the normally 'closed contact Il a-43a opens. When the relay releases, the bell circuit will remain open and it follows, therefore, that the bell will only ring during the picking up of the relay. This action is frequently desirable in centralized trafilc control and remote control circuits and heretofore has required two relays to obtain it.

Although I have herein shown and described contact mechanism embodying my invention applied to only one form of relay, it will be under-,

stood that this contact mechanism may readily be applied to other forms of relays. It will also be understood that various changes and modifications in the contact mechanism embodying my invention may be made in accordance with the scope of the appended claims, without departing from the spirit and scope of my invention.

Having thus described my invention, what I claim is:

l. A contact mechanism-comprising four superposed contact fingers disposed in parallel spaced relation, two of said fingers being relatively movable and the remaining two fingers being relatively fixed, each said movable finger cooperating with a different one of said fixed fingers to form a switch means, and a toggle link connecting the free ends of said movable fingers, the parts being so proportioned and so adjusted that the inherent resiliency of the one movable finger will cause the switch means including such finger to be normally open and the other switch means to be normally closed and that upon movement of said one movable finger in one direction said normally closed switch means will open with a snap action due to said toggle link but not until after said normally open switch means has closed.

2. A contact mechanism comprising four flexible contact fingers supported at one end in superposed parallel spaced relation, two of said fingers being relatively fixed and the remaining two fingers being relatively movable, each said movable finger cooperating with one of said fixed fingers to form a switch means, a U-shaped return bend on one of said movable fingers, and a toggle link disposed between the free leg of said Ushaped return bend and the free end of the other movable finger, the parts being so proportioned and so arranged that the switch means including said one movable finger will be normally open and the other switch means will be normally closed but that movement of said one finger past the position in which said normally open switch means closes will cause said other switch means to open with a snap action due to the toggle action caused by the inherent resiliency or the movable fingers.

3. A contact mechanism comprising a first movable contact finger biased by its own resiliency to one position and movable to another poaitlon, a first fixed contact finger cooperating with said first movable finger to form a first switch means and so adjusted that said first switch means will be normally open but will become closed in response to movement of said first movable finger toward its other position, a U-shaped return bend formed on the free end of said first movable contact finger, a second movable contact finger, a toggle member connecting said U-shaped return bend with the free end of said second movable finger in such manner that the free end of said second movable finger will be biased to a position above or below that which it tends to assume due to its own resiliency according as said first movable finger occupies its one or its other position, and a second fixed finger cooperating with said second movable finger to form a switch means which is closed or open according as the free end of said second movable finger is above or below the position it tends to assume due to its own resiliency.

4. A contact mechanism comprising a first movable contact finger biased by its own resiliency to one position and movable to another pcaition, a first fixed contact finger cooperating with said first movable finger to form a first switch means and so adjusted that said first switch means will be normally open but will become closed in response to movement of said first movable finger toward its other position, a U-shaped return bend formed on the free end of said first movable contact finger, a second movable contact finger, a toggle member connecting said U-shaped return bend with the free end of said second movable finger in such manner that the free end of said second movable finger will be biased to a position above or below that which it tends to assume due to its own resiliency according as said first movable finger occupies its one or its other position, and a second fixed finger cooperating with said second movable finger to form a switch means which is closed or open according as the free end of said second' movable finger is above or below the position it tends to assume due to its own resiliency, the resiliency of said first movable finger being sufiicient to return it to its one position upon being released following its movement to its other position.

ARTHUR E. DODD,

REFERENCES CITED The following references are of record in the 

